include/linux/kprobes.h

   1 #ifndef _LINUX_KPROBES_H
   2 #define _LINUX_KPROBES_H
   3 /*
   4  *  Kernel Probes (KProbes)
   5  *  include/linux/kprobes.h
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  *
  21  * Copyright (C) IBM Corporation, 2002, 2004
  22  *
  23  * 2002-Oct     Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
  24  *              Probes initial implementation ( includes suggestions from
  25  *              Rusty Russell).
  26  * 2004-July    Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
  27  *              interface to access function arguments.
  28  */
  29 #include <linux/config.h>
  30 #include <linux/list.h>
  31 #include <linux/notifier.h>
  32 #include <linux/smp.h>
  33 #include <asm/kprobes.h>
  34
  35 struct kprobe;
  36 struct pt_regs;
  37 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  38 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  39 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  40                                        unsigned long flags);
  41 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  42                                        int trapnr);
  43 struct kprobe {
  44         struct hlist_node hlist;
  45
  46         /* location of the probe point */
  47         kprobe_opcode_t *addr;
  48
  49         /* Called before addr is executed. */
  50         kprobe_pre_handler_t pre_handler;
  51
  52         /* Called after addr is executed, unless... */
  53         kprobe_post_handler_t post_handler;
  54
  55         /* ... called if executing addr causes a fault (eg. page fault).
  56          * Return 1 if it handled fault, otherwise kernel will see it. */
  57         kprobe_fault_handler_t fault_handler;
  58
  59         /* ... called if breakpoint trap occurs in probe handler.
  60          * Return 1 if it handled break, otherwise kernel will see it. */
  61         kprobe_break_handler_t break_handler;
  62
  63         /* Saved opcode (which has been replaced with breakpoint) */
  64         kprobe_opcode_t opcode;
  65
  66         /* copy of the original instruction */
  67         struct arch_specific_insn ainsn;
  68 };
  69
  70 /*
  71  * Special probe type that uses setjmp-longjmp type tricks to resume
  72  * execution at a specified entry with a matching prototype corresponding
  73  * to the probed function - a trick to enable arguments to become
  74  * accessible seamlessly by probe handling logic.
  75  * Note:
  76  * Because of the way compilers allocate stack space for local variables
  77  * etc upfront, regardless of sub-scopes within a function, this mirroring
  78  * principle currently works only for probes placed on function entry points.
  79  */
  80 struct jprobe {
  81         struct kprobe kp;
  82         kprobe_opcode_t *entry; /* probe handling code to jump to */
  83 };
  84
  85 #ifdef CONFIG_KPROBES
  86 /* Locks kprobe: irq must be disabled */
  87 void lock_kprobes(void);
  88 void unlock_kprobes(void);
  89
  90 /* kprobe running now on this CPU? */
  91 static inline int kprobe_running(void)
  92 {
  93         extern unsigned int kprobe_cpu;
  94         return kprobe_cpu == smp_processor_id();
  95 }
  96
  97 extern int arch_prepare_kprobe(struct kprobe *p);
  98 extern void arch_copy_kprobe(struct kprobe *p);
  99 extern void arch_remove_kprobe(struct kprobe *p);
 100 extern void show_registers(struct pt_regs *regs);
 101
 102 /* Get the kprobe at this addr (if any).  Must have called lock_kprobes */
 103 struct kprobe *get_kprobe(void *addr);
 104
 105 int register_kprobe(struct kprobe *p);
 106 void unregister_kprobe(struct kprobe *p);
 107 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 108 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 109 int register_jprobe(struct jprobe *p);
 110 void unregister_jprobe(struct jprobe *p);
 111 void jprobe_return(void);
 112
 113 #else
 114 static inline int kprobe_running(void)
 115 {
 116         return 0;
 117 }
 118 static inline int register_kprobe(struct kprobe *p)
 119 {
 120         return -ENOSYS;
 121 }
 122 static inline void unregister_kprobe(struct kprobe *p)
 123 {
 124 }
 125 static inline int register_jprobe(struct jprobe *p)
 126 {
 127         return -ENOSYS;
 128 }
 129 static inline void unregister_jprobe(struct jprobe *p)
 130 {
 131 }
 132 static inline void jprobe_return(void)
 133 {
 134 }
 135 #endif
 136 #endif                          /* _LINUX_KPROBES_H */